In many large server applications, processors along with their associated electronics (e.g., memory, disk drives, power supplies, etc.) are packaged in removable drawer configurations stacked within a rack or frame. In other cases, the electronics may be in fixed locations within the rack or frame. Typically, the components are cooled by air moving in parallel air flow paths, usually front-to-back, impelled by one or more air moving devices (e.g., fans or blowers). In some cases it may be possible to handle increased power dissipation within a single drawer by providing greater air flow, through the use of a more powerful air moving device or by increasing the rotational speed (i.e., RPMs) of an existing air moving device. However, this approach is becoming problematic.
The sensible heat load carried by the air exiting the rack is stressing the ability of the room air conditioning to effectively handle the load. This is especially true for large installations with “server farms” or large banks of computer racks close together. In such installations not only will the room air conditioning be challenged, but the situation may also result in recirculation problems with some fraction of the “hot” air exiting one rack unit being drawn into the air inlet of the same rack or a nearby rack. This re-circulating flow is often extremely complex in nature, and can lead to significantly higher rack inlet temperatures than expected. In such installations, liquid cooling (e.g., water cooling) is an attractive technology to assist in managing the higher heat fluxes. The liquid absorbs the heat dissipated by the components/modules in an efficient manner, and the heat can be ultimately transferred from the liquid to an outside environment, whether air or other liquid coolant.
To introduce liquid cooling into one or more computer server units, it is necessary that tubings and fittings be provided which are acceptable within a typical electronics rack, such as a server cabinet.